Utilization of prior clinical experience has been impeded by frailities of memory, the statistical biases of retrospectively recorded data, and importantly, by difficult access to recorded clinical information. These problems are particularly acute in the major rheumatic diseases, where long patient courses, frequent fluctuations, interactions of problems in many organs, and uncertain natural history combine to create complicated clinical data. The chronic disease data bank provides substantial solutions to many of these problems. ARAMIS is a pilot Rheumatic Disease computer data bank network building upon previous national projects in standardization of clinical description on arthritis. ARAMIS contains 15 million data items on 13,845 arthritis patients seen over 20,000 patient years at over a dozen institutions. The network enables pooling of clinical data between institutions, inter-institutional studies, rapid access to large quantities of clinical data, and provides computer consultation and clinical decision procedures based upon this data. It demonstrates the feasibility of a chronic disease network, including successful function, fruitful collaboration, and documentation of utilization. Evaluation of the contribution of the system to patient care, teaching, and research is being carried out by an evaluation team of biostatisticians, health economists, and physicians. The data bank is an essential tool to relate medical process to patient outcome. It can pinpoint areas of non-productive effort, leading to more efficient practice. By increasing the efficiency of clinical management sudies it provides new scientific information to the clinician. And by recognizing unique characteristics of each patient it can assist in the development of individualized approaches to patient management. ARAMIS provides access to detailed, uniform clinical data for larger numbers of arthritis patients than ever previously available. Proceeding in concert with the National Arthritis Plan, it seeks to provide the physician and the investigator with better information with which to manage the patient.